1. Field of the Invention
The present invention relates to fixation of a tendon/bone graft during a surgical procedure and particularly, to the formation of a bore in bone used in anchoring the bone/tendon graft.
2. Description of Related Art
Anterior cruciate ligament reconstruction includes replacing the ligament with a tendon/bone graft. During arthroscopic knee surgery, for example, a surgeon can form a tunnel through the tibia, intra articular joint and femur to receive a bone-tendon-bone graft. The graft must be adequately secured. Typically this is accomplished by tying sutures over ligament buttons, or by using staples, unicortical screw posts or interference screws.
One conventional method of fixation of a tendon/bone graft is to harvest a plug from the patellar tendon. Each plug of the bone-tendon-bone graft is harvested typically in semi-circular cross-section with a semi-circular gouge and is conventionally sized. Next, as shown in FIG. 1, a graft socket 400 is drilled into bone 410 with a conventional twist drill bit 420 which breaks-up bone fragments 430 and discharges those fragments from the socket 400. The bone fragments 430 are extracted from the socket since they move along the helical groove 440 of the drill bit 420 until the fragments exit the socket,. as shown by the arrows F in FIG. 1. The plug is then inserted into the socket and fixed therein, preferably by a screw. The sockets created during the conventional extraction drilling process are thin-walled, having open, exposed marrow elements, which limit the likely success of the mechanical fixation of the graft, since the chances of screw migration, divergence, and convergence are increased.